Integrated circuits are what power many of today's consumer electronics. Integrated circuits can be found in cellphones, video cameras, portable music players, computers, and even automobiles. As customer demand improves integrated circuit (IC) performance, faster, more reliable, and higher-density circuits, need to be produced. Various techniques, such as, ball grid array (BGA), flip-chip, and multi-chip modules (MCM), have been developed to meet the continued demands for improving system performance and hardware capabilities, while the space in which to provide these improved hardware capabilities continues to decrease.
MCM may include two or more chips stacked one on top of another (i.e.—vertically stacked). This mounting technique permits a higher density of chips or integrated circuits on the MCM substrate. The MCM substrate may include one or more layers of electrically conductive material separated by dielectric materials.
Although vertically stacked MCM's may increase the effective density of chips, over that of horizontally placed MCM components, it has the disadvantage in that the MCM's must usually be assembled before the component chips and chip connections can be tested. These extra manufacturing steps can lead to increased cost and decreased product yield if the chips are defective.
Another common problem associated with vertically stacked MCM's is that the bottom chip must be larger than the top chip to accommodate the plurality of bond pads located on the bottom chip. Due to the constraint of limited space available for mounting individual chips on a substrate, the larger configuration of the bottom chip decreases the number of chips per semiconductor wafer, and correspondingly, increases the cost of manufacturing. Additionally, since the top chip must be made smaller than the bottom chip, the top chip possesses less space for electronic components and circuits, which is counter to the goal of developing higher density integrated circuits.
Another problem of vertically stacked MCM's is the lack of sufficient thermal dissipation. Insufficient thermal dissipation can lead to package over heating and chip bonding problems. Chip bonding problems arise when high temperatures trigger thermal expansion differences between disparate materials within a package. These differences in thermal expansion rates can lead to warpage, delamination and chip cracking problems.
Thus, a need still remains for a reliable integrated circuit package system and method of fabrication, wherein the integrated circuit package system possesses a high-density of integrated circuits while preventing warpage and delamination problems. In view of the ever-increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Moreover, the ever-increasing need to save costs, improve efficiencies, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.